IPA: /ʌnˈklæsɪfaɪə/
KK: /ʌnˈklæsɪfaɪə/
Not able to be placed into a specific category or group.
The artist's work is so unique that it is often considered unclassifiable.
Unclassifiable → It is formed from "un-" (meaning not) and "classificare" (from Latin, meaning to classify) and "-able" (meaning capable of). The word means not capable of being classified or categorized.
Think of 'not' ('un-') being able to 'classify' something — that's why unclassifiable means it cannot be categorized.